People have known dolphins for centuries. In the middle of the last century, a serious study of these amazing ocean inhabitants began. And the fact that they are amazing and even unique is impossible to doubt. For example, the distant ancestors of cetaceans once lived on land, and then, for some reason, returned to the ocean. Dolphins breathe oxygen. But only recently it became clear how they manage to sleep in the ocean without drowning. And, perhaps, dolphins have prepared many more mysteries and discoveries for scientists.
These amazing dolphins
Scientists call dolphins the intellectuals of the sea for a reason. And the point is not at all that the dolphin's brain weighs more than the human brain. Scientists have determined that dolphins come up with names for themselves, know the names of their relatives. Moreover, they are able to talk about someone else, calling him by name. On earth, no one except man possesses such capabilities.
In addition, research has shown that dolphin language, like human language, is subdivided into sounds, syllables, words, sentences, simple and complex, and paragraphs.
Dolphins are far superior to humans in terms of sound. They can conduct a dialogue, being a kilometer from each other. And if necessary, they are able to hear the other and 20 km away.
The dolphin's body is extremely functional. The front fins act as rudders, while the rear fins act as a propeller. They are capable of speeds of 60-65 km / h.
Gray paradox, and more
The famous "Gray paradox" is associated with the high speed capabilities of dolphins.
Professor Gray, a specialist in biomechanics, calculated that in order to develop such significant speeds with the resistance that water has to any moving object, dolphins must be 7 times stronger.
Max Cameron tried to explain Gray's paradox. He believed that it was all about the elastic skin of the dolphin. It is known that all objects, when moving in water, create vortex flows, which take a lot of energy to extinguish.
The dolphin does not create vortex flows, it is, as it were, screwed into the water. And his skin has unique properties - it self-regulates, and can change its elasticity at any time in any part of the body. When interacting with water, these properties contribute to damping turbulence directly next to the animal's body.
Later, Professor Hagiwara, an employee of the Kyoto Institute of Technology, found out that the entire outer layer of dolphin skin is completely renewed every two hours. The tests carried out made it possible to establish that the particles of the discarded layer of the skin destroy the formed vortex flows and damp the water turbulence. But even this is not able to unambiguously explain why dolphins are able to develop such a high speed.
In the end, it turned out that Gray was still wrong, and the dolphins are stronger than he thought. For example, a bottlenose dolphin has a tail kick that is 10 times more powerful than previously thought.
Dolphins can also dive quite deep. A trained Atlantic bottlenose dolphin is capable of diving to a depth of 300m and staying underwater for 12-15 minutes.
How can an animal that breathes oxygen do without it for so long? It turns out that the tissues of the dolphin's body are capable of storing oxygen. If necessary, the animal's body uses these previously accumulated reserves.
